Tower cranes



J. F. STAPLES April 9, 1963 TOWER CRANES Filed May 9, 1962 3Sheets-Sheet 1 J. F. STAPLES April 9, 1963 TOWER CRANES 5 Sheets-Sheet 2Filed May 9, 1962 lnvenlor JAMES FREDERICK STAPLES J. F. STAPLES April9, 1963 TOWER CRANES 3 Sheets-Sheet 5 Filed May 9, 1962 Jim InventorJAMES FREDERICK STAPLES United States Patent 3,084,806 TOWER CRANESJames Frederick Staples, 20 St. Lawrence St, Greenwich, New South Wales,Australia Filed May 9, 1962, Ser. No. 193,536 Claims. (Cl. 212-46} Thisinvention relates to tower cranes, and in particular to such craneswhich may be folded into a relatively small space for stowing.

Tower cranes of the type to which this invention applies consistessentially of a vertical tower and a boom projecting from the tower atan intermediate point upon it.

Cranes of this general type are already known for heavy loads and highlift, that part of the tower above the boom foot being necessary toenable the boom to be supported and moved by lufiing lines passing fromthe boom upwards to the top of the tower and so forming a stabletriangular boom-supporting configuration.

The long tower and boom members normally prevent stowage withoutdismantling these members.

This is particularly disadvantageous where the crane has to betransported from job to job. For example, the road transport regulationslimit the maximum dimensions of road transport vehicles in height, widthand length and it is a difiicult and time consuming matter to dismantlea crane, stow it for transport within these limits and reassemble it onthe new site.

An object of the invention is to provide a structure of tower crane bywhich it may be folded down to compact size without dismantling thecrane.

Another object is to enable relatively large tower cranes to be operatedfrom a vehicle and to be stowed within the regulation limits for roadtransport on that vehicle.

Various arrangements have been proposed to this end, such as telescopingthe tower in sections and stowing the boom underneath the telescopedtower.

In all such arrangements however the length of the boom or that part ofthe tower above the boom or both have made for great length in stowedposition.

A further object of the invention is to provide a tower crane in whichthe stowed length is not appreciably longer than the boom length, andmay in some embodiments be much shorter.

According to the invention, the tower is mounted on a base and consistsof a first part below the boom foot, and a second part above it, thetower being mounted on said base for pivotal movement in a directionaway from said boom. By this construction the :boom lies above the towerin stowed position.

The second part of said tower may be collapsed to lie substantiallywithin the length of said first part to give further economy of spacewhen stowed.

In order that the invention may be better understood, variousembodiments will now be described, by way of example only, in relationto the accompanying drawings, in which:

FIG. 1 represents a mobile tower crane in erected position,

3,8 1,896 Patented Apr. 9, 1963 Hce mounted upon an articulatedsemi-trailer vehicle, the tray 10 of which has four axles, two in frontand two at the rear.

The tray 10 supports a turntable 11, centred between the axle pairs,upon which the whole crane structure is mounted to pivot round avertical axis 12.

The crane mast rests upon a :base consisting of triangular member 13rigidly secured along one side to the turntable 11. Pivoted :to base 13at point 14 is a second triangular member 15. A third triangular member16 is pivoted to member 15 at 17, and the boom 18 is pivotally attachedto this third member at point 19; The members 1%, 16 comprise the firstpart of the crane tower.

It will be understood that each triangular member consists of twotriangular side pieces rigidly joined together by at least onecross-piece. The term triangular member when used in the claims of thisspecification is to be understood in the above sense.

The triangular member 16 has no cross-piece at point 33 to allow members29, 21 to fold through it on stowing (as shown in FIGURE 2). The viewsin the drawings, of course, show only the front triangular side piece ofeach triangular member.

The pivots at points 14 and 17 each consist, either of a separate pivoton each triangular side piece, or of an elongated pivot extending acrossfrom one to the other side piece.

A first rigid mast-like member 20 is also pivoted at point 19 and has asecond similar mast-like member 21 pivotally attached to it at its upperend 22. Members 20, 21 comprise the second part of the crane tower.

Although these mast-like members are shown only as an elongated beam inthe drawings, it is to be understood that they may each consist of twoside-beams rigidly cross-connected and that their pivots at 19 and 22may therefore be of the double type described in relation to thetriangular members.

The counterweight beam 27 (to be described later) and the boom 18 willalso be of a similar form and with similar pivots.

The general configuration of the crane is therefore a tower having aboom 13 projecting from a point .19 upon it intermediate its ends, thetower consisting of a first part (members 15, 16) below the point 19 anda second part (members 26, 21) above the point 19 and said first partbeing pivoted at 14 on a base 13.

For raising and lowering the tower between stowed horizontal positionand working vertical position a hydraulic ram 23 extends from a point onthe axis 12 to the apex 24 of member 15 remote from the boom 18.

This ram is of the double-acting type, that is, it is capable ofretaining its degree of extension against forces acting both upwards anddownwards upon it.

It will be obvious that a mechanical jack of similar characteristicsmaybe substituted.

A counterweight 25 lies in the stowed position (FIG- URE 2) directlyabove the rear pair of axles on the tray 10, while a secondcounterweight 26 lies above the front pair of axles, the twocounterweights 25, 26 being equally spaced from the axis 12.

Counterweight 25 is attached, by a pivot passing through its centre ofgravity, to a rigid arm 27 which is radial to the axis 12 and is pivotedfor vertical movement near to the point 28 of base 13.

It will be clear from the description thus far that the rigid members13, 15, 16, 20, and 21 are all pivotally con nected and will have nostructural stability without some further connections.

These further connections are provided by tensioned flexible ties suchas steel ropes (shown as single lines in FIGURE 1) and will now bedescribed.

The counterweight 25 is connected to point 14 of member 13 and point 24of member by ties 29, 39 respectively.

Points 28 on member 13 and 24 on member 15 are tied as shown at 31.Point 24 is tied as shown at 32 to point 33 on member 16, and point 33to point 34 on the second mast-like member 21, as shown at 35.

Point 33 is also tied to point 22 at the junction of the members 20, 21,as shown at 36.

Each tie described will, of course, consist of at least two ropes, oneat each side of the tower. The phrase flexible tie" is to be understoodin this sense in the description and claims. In addition to the ties,which are all of fixed length and secured at each end to their anchorpoints, the tip 37 of boom 18 is connected (in known manner) by severalfalls of lufling rope to the tip 34 of the member 21.

It will be understood that the invention includes a structure in whichthe flexible ties defined above may be replaced by rigid members,hydraulic rams or mechanical jacks. In particular, the tie 31 betweenpoints 24 and 28 may be replaced by a double-acting hydraulic ram or ajack (not shown).

The last fall is continued down from point 34 to a drum (not shown) nearpoint 28, so that haulage by the drum on the lufling rope moves thepoints 37 and 34 closer together and luifs the boom lb.

When fully erected (as shown in FIGURE 1) it will easily be understoodthat the weight of the boom 18, and any load carried from it, will holdall ties taut, so that the whole tower structure will be completelystable in the plane of the boom and tower.

Lateral stability is gained by the double construction of the membersand pivots and by the double ties previously described.

FIGURE 2 shows the crane in stowed position. In this figure, the tiesand luffing falls and rope are omitted for clarity. It will be obvious,however, that all ties will be un-tensioned and loose.

The luifing falls pass around from the tip 37 of boom 13 and are foldedaround points 19 and 22 to reach the tip 34 of member 21. Thence theluffing rope passes to its drum near point 28.

With this arrangement, haulage of the lufiing rope will rotate members20, 21 counter-clockwise from under member 16, owing to the aggregatetensions in the luffing falls being greater than that in the lufiingrope.

To erect the crane, the ram 23 is expanded, thus pivoting member 15about point 14 counter-clockwise in FIGURE 2.

To prevent boom 18 tipping forward and downward, a hydraulic ram 38 maybe provided to give it a preliminary lift.

As the mast rises, the members ill, 21 will drop away under the actionof gravity until 2% and then 21 in turn clearthe tray 10.

The luffing rope is now wound in, and members 20, 21 are pulled roundbeyond the member 16 as described above until the ties 35 and 36tighten. The boom weight acting through members 2%), 21 and ties 35, 36then pivots the member 16 to tighten the tie 32 and the boom weight(acting through the lufling falls and steadied by the double-acting ram23) tightens tie 31, thus completing the tower structure.

Before the tower reaches the vertical, the tie 3t) tightens, andcounterweight 25 on its arm 27 is lifted clear of the tray 10.

In this position the whole crane may be turned through 180, as shown inFIGURE 3. The counterweight 25 can now, by contracting ram 23, belowered upon weight 25 and secured to it, by any suitable detachablefastening (not shown), so that the tower, when raised to vertical, hasthe double counterweights 25, 26 attached.

Thus, although the counterweights Z5 and 26 are carried fortransportation one above each pair of axles, both are readily attachedto the arm 27 when the crane is in 4 use, merely by using the erectingmechanism of the crane itself.

Since the counterweight 25, during the first stages of erection of thetower, would exert a compressive force upon the ram 23 through tie 3b,the further tie 29 may be provided to take some of the strain, but is sodimensioned that its tension is transferred to tie 30 on full erectionof the tower. By prestressing ram 23 by tie 39, tie 31 may in some casesbe omitted.

As will be seen from the drawings, the crane, owing to the fact that theboom is on top of the collapsed tower and not beneath it, can be stowedin a length little, if at all, greater than the length of the boomitself.

The stowage of the boom on top has the additional advantage that it maylie beyond the tray 1b and above the vehicle cabin, so that the trayneed not be the full length of the boom.

If the tower were rigid, the upper part of the tower between the boompivot and the top would add to the stowed length at the rear. The topsection, however, is folded as shown beneath the remainder of the towerso that this extra length is also avoided.

The combination of pivoted rigid members 15, 16 with flexible ties 31,32 in the first part of the tower allows a further economy in length,for, in the stowed position, the ties are slackened and the rigidmembers move into a smaller length.

Therefore these three factors together enable the maximum economy instowage space for a given crane size and capacity, or alternativelyallow a much larger crane to be stowed in a given spacev Referring toFEGURES 4 to 7, the first part of the tower comprises a triangularmember 40 pivoted at 41 on a base structure (not shown) rotatable on aturntable (not shown) about an axis 42 (FIGURES 4 and 7), the toweritself having a centre axis 43 (FIGURE 7) offset from the centre line ofthe supporting vehicle and from the turntable axis 42. The member 40 ispivoted by a double-acting hydraulic ram 55.

The second part of the tower comprises a mast-like member 4 pivoted at45 on the member 40* and a second mast-like member 46 pivoted at 47 onsaid first member 44.

The boom in this embodiment extends as before from a point on thejunction of the first and second parts of the tower, but is made inthree parts. The rigid member 48 nearest the foot is hinged to theintermediate rigid member 49 along a vertical hinge line 50, so that 49may be hinged sideways (up from the plane of the drawing) with respectto member 48. The hinge 50 is locked in working position and releasedfor stowiug. The third rigid member 51 of the boom is pivoted at 52 tomember 49, vertical movement thereon resulting.

For stowing, member 51 is first hinged downwards to lie underneath andadjacent the boom as shown in FIG- URE 5. Members 49 and 51 are thentogether hinged horizontally about line 50 to lie beside member 48 asshown in FIGURES 6 and 7. It will be seen that the offsetting of theaxis 43 from the centre-line of the vehicle and from turntable axis 42enables the whole lower part of the tower and the boom to be stowedwithin the width of the vehicle.

The members 44 and 46 are positioned by the hydraulic ram 53 and therotary hydraulic unit 54 respectively. For stowing, the member 44 isrotated clockwise by ram 53 and member 46 anti-clockwise by the unit 54to rest within the member 44 and extend vertically downwards in thefully-stowed position (FIGURE 6). In an alternative arrangement (notshown) the member 44 may be rotated anti-clockwise and the member 46clockwise so that members 44 and 46 may lie vertically downwards andupwards respectively in stowed position. This arrangement may allow themember 44 to be longer without limiting the length of member 46.

The embodiment of FIGURES 4 to 7 therefore enables stowage in a minimumof space, the long boom being stowed in parallel parts with the firstpart 48 lying above the lower part of the tower, and the upper part ofthe tower (members 44 and 46) being stowed in such a way as to take upvery little space indeed.

The various pivoting movements may all be carried out by hydraulicmeans, a common source of pressure fluid serving to actuate them all.

What I claim is:

1. A tower crane comprising a turntable rotatable round a vertical axis,a base on said turntable, a tower on said base, the axis of said towerbeing offset from said vertical axis, a boom projecting from a pointintermediate the ends of said tower, said tower being mounted on saidbase for pivotal movement in a direction away from said boom, said boomincluding a first rigid member nearest said point and a second rigidmember connected to that end of said first rigid member remote from saidpoint for sideways hinging movement to a position adjacent andsubstantially parallel to said first rigid member.

2. A tower crane according to claim 1, wherein said boom comprises athird rigid member connected to that end of said second member furthestfrom said point for Vertical pivotal movement to a positionsubstantially parallel to and immediately beneath said second member.

3. A tower crane comprising a base, a tower mounted on said base, a boomprojecting from a point upon said tower intermediate its ends, the towerconsisting of a first part below said point and a second part above it,said first part being pivoted to said base for movement in a directionaway from said boom, said second part of said tower comprising a firstmast-like member mounted for pivotal movement on top of said first partand a second mast-like member pivotally mounted on top of said firstmast-like member, said two mast-like members being so shaped that theynest one within the other when pivoted to a contiguous position.

4. A tower crane comprising a base, a tower mounted on said base, a boomprojecting from a point upon said tower intermediate its ends, the towerconsisting of a first part below said point and a second part above it,said first part being pivoted to said base for movement in a directionaway from said boom, said second part of said tower comprising a firstrigid mast-like member pivoted on the upper portion of said first partof said tower and a second rigid mast-like member pivoted on the upperportion of said first mast-like member.

5. A tower crane comprising a base, a tower mounted on said base, a boomprojecting from a point upon said tower intermediate its ends, the towerconsisting of a first part below said point and a second part above it,said first part being pivoted to said base for movement in a directionaway from said boom, said first part comprising triangular members lyingabove one another in working position and pivotally connected, theapices of adjacent triangular members remote from the boom beingconnected by flexible ties, said second part comprising a firstmast-like member attached to the upper portion of said first part forpivotal movement away from said boom and a flexible tie connecting thatapex of the upper triangular member remote from the boom to the upperextremity of said first mast-like member.

6. A tower crane in accordance with claim 5, wherein a second mast-likemember is connected to the upper extremity of said first mast-likemember for pivotal movement away from said boom, the upper extremity ofsaid second member being connected to that apex of the upper triangularmember remote from the boom by a flexible tie.

7. A tower crane comprising a turntable rotatable round a vertical axis,a base on said turntable, a tower on said base, a boom projecting from apoint intermediate the ends of said tower, said tower consisting of afirst part below said point and a second part above it, said first partbeing mounted on said base for pivotal movement in a direction away fromsaid boom, a rigid arm radial to said axis and pivoted on said base forvertical movement, a first counterweight on said arm, means for liftingsaid counterweight on said arm when said tower is in working position, asecond counterweight, said first and second counterweights being equallyspaced from said axis, and detachable means for fastening saidcounterweights together one above the other.

8. A tower crane comprising a base, a tower mounted on said base, a boomprojecting from a point upon said tower intermediate its ends, the towerconsisting of a first part below said point and a second part above it,said first part being pivoted to said base for movement in a directionaway from said boom, said boom including a first rigid member nearestsaid point, a second rigid member connected to that end of said firstmember remote from said point for sideways hinging movement to aposition adjacent and substantially parallel to said first member and athird rigid member connected to that end of said second member furthestfrom said point for vertical pivotal movement to a positionsubstantially parallel to and immediately beneath said second member.

9. A tower crane according to claim 8, wherein said second part of saidtower is pivoted on the upper portion of said first part.

*10. A tower crane according to claim 8, wherein said second part ofsaid tower comprises a first mast-like member pivoted to the top of saidfirst part of said tower and a second mast-like member pivoted to thetop of said first mast-like member, both mast-like members beingpositively adjustable by hydraulic means.

References Cited in the file of this patent UNITED STATES PATENTS2,383,172 Wagner et al. Aug. 21, 1945 2,831,589 Way Apr. 22, 1958FOREIGN PATENTS 509,657 Italy Jan. 15, 1955 1,001,808 Germany Jan. 31,1957 1,022,778 Germany Jan. 16, 1958 1,075,812 Germany Feb. 18, 19601,091,304 Germany Oct. 20, 1960

1. A TOWER CRANE COMPRISING A TURNTABLE ROTATABLE ROUND A VERTICAL AXIS,A BASE ON SAID TURNTABLE, A TOWER ON SAID BASE, THE AXIS OF SAID TOWERBEING OFFSET FROM SAID VERTICAL AXIS, A BOOM PROJECTING FROM A POINTINTERMEDIATE THE ENDS OF SAID TOWER, SAID TOWER BEING MOUNTED ON SAIDBASE FOR PIVOTAL MOVEMENT IN A DIRECTION AWAY FROM SAID BOOM, SAID BOOMINCLUDING A FIRST RIGID MEMBER NEAREST SAID POINT AND A SECOND RIGIDMEMBER CONNECTED TO THAT END OF SAID FIRST RIGID MEMBER REMOTE FROM SAIDPOINT FOR SIDEWAYS HINGING MOVEMENT TO A POSITION ADJACENT ANDSUBSTANTIALLY PARALLEL TO SAID FIRST RIGID MEMBER.